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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "stack_map.h"
#include <iomanip>
#include <stdint.h>
#include "art_method.h"
#include "base/indenter.h"
#include "base/stats-inl.h"
#include "oat_quick_method_header.h"
#include "scoped_thread_state_change-inl.h"
namespace art {
// The callback is used to inform the caller about memory bounds of the bit-tables.
template<typename DecodeCallback>
CodeInfo::CodeInfo(const uint8_t* data, size_t* num_read_bits, DecodeCallback callback) {
BitMemoryReader reader(data);
std::array<uint32_t, kNumHeaders> header = reader.ReadInterleavedVarints<kNumHeaders>();
ForEachHeaderField([this, &header](size_t i, auto member_pointer) {
this->*member_pointer = header[i];
});
ForEachBitTableField([this, &reader, &callback](size_t i, auto member_pointer) {
auto& table = this->*member_pointer;
if (LIKELY(HasBitTable(i))) {
if (UNLIKELY(IsBitTableDeduped(i))) {
ssize_t bit_offset = reader.NumberOfReadBits() - reader.ReadVarint();
BitMemoryReader reader2(reader.data(), bit_offset); // The offset is negative.
table.Decode(reader2);
callback(i, &table, reader2.GetReadRegion());
} else {
ssize_t bit_offset = reader.NumberOfReadBits();
table.Decode(reader);
callback(i, &table, reader.GetReadRegion().Subregion(bit_offset));
}
}
});
if (num_read_bits != nullptr) {
*num_read_bits = reader.NumberOfReadBits();
}
}
CodeInfo::CodeInfo(const uint8_t* data, size_t* num_read_bits)
: CodeInfo(data, num_read_bits, [](size_t, auto*, BitMemoryRegion){}) {}
CodeInfo::CodeInfo(const OatQuickMethodHeader* header)
: CodeInfo(header->GetOptimizedCodeInfoPtr()) {}
CodeInfo CodeInfo::DecodeGcMasksOnly(const OatQuickMethodHeader* header) {
CodeInfo code_info(header->GetOptimizedCodeInfoPtr());
CodeInfo copy; // Copy to dead-code-eliminate all fields that we do not need.
copy.stack_maps_ = code_info.stack_maps_;
copy.register_masks_ = code_info.register_masks_;
copy.stack_masks_ = code_info.stack_masks_;
return copy;
}
CodeInfo CodeInfo::DecodeInlineInfoOnly(const OatQuickMethodHeader* header) {
CodeInfo code_info(header->GetOptimizedCodeInfoPtr());
CodeInfo copy; // Copy to dead-code-eliminate all fields that we do not need.
copy.number_of_dex_registers_ = code_info.number_of_dex_registers_;
copy.stack_maps_ = code_info.stack_maps_;
copy.inline_infos_ = code_info.inline_infos_;
copy.method_infos_ = code_info.method_infos_;
return copy;
}
size_t CodeInfo::Deduper::Dedupe(const uint8_t* code_info_data) {
writer_.ByteAlign();
size_t deduped_offset = writer_.NumberOfWrittenBits() / kBitsPerByte;
// The back-reference offset takes space so dedupe is not worth it for tiny tables.
constexpr size_t kMinDedupSize = 32; // Assume 32-bit offset on average.
// Read the existing code info and find (and keep) dedup-map iterator for each table.
// The iterator stores BitMemoryRegion and bit_offset of previous identical BitTable.
std::map<BitMemoryRegion, uint32_t, BitMemoryRegion::Less>::iterator it[kNumBitTables];
CodeInfo code_info(code_info_data, nullptr, [&](size_t i, auto*, BitMemoryRegion region) {
it[i] = dedupe_map_.emplace(region, /*bit_offset=*/0).first;
if (it[i]->second != 0 && region.size_in_bits() > kMinDedupSize) { // Seen before and large?
code_info.SetBitTableDeduped(i); // Mark as deduped before we write header.
}
});
// Write the code info back, but replace deduped tables with relative offsets.
std::array<uint32_t, kNumHeaders> header;
ForEachHeaderField([&code_info, &header](size_t i, auto member_pointer) {
header[i] = code_info.*member_pointer;
});
writer_.WriteInterleavedVarints(header);
ForEachBitTableField([this, &code_info, &it](size_t i, auto) {
if (code_info.HasBitTable(i)) {
uint32_t& bit_offset = it[i]->second;
if (code_info.IsBitTableDeduped(i)) {
DCHECK_NE(bit_offset, 0u);
writer_.WriteVarint(writer_.NumberOfWrittenBits() - bit_offset);
} else {
bit_offset = writer_.NumberOfWrittenBits(); // Store offset in dedup map.
writer_.WriteRegion(it[i]->first);
}
}
});
if (kIsDebugBuild) {
CodeInfo old_code_info(code_info_data);
CodeInfo new_code_info(writer_.data() + deduped_offset);
ForEachHeaderField([&old_code_info, &new_code_info](size_t, auto member_pointer) {
if (member_pointer != &CodeInfo::bit_table_flags_) { // Expected to differ.
DCHECK_EQ(old_code_info.*member_pointer, new_code_info.*member_pointer);
}
});
ForEachBitTableField([&old_code_info, &new_code_info](size_t i, auto member_pointer) {
DCHECK_EQ(old_code_info.HasBitTable(i), new_code_info.HasBitTable(i));
DCHECK((old_code_info.*member_pointer).Equals(new_code_info.*member_pointer));
});
}
return deduped_offset;
}
StackMap CodeInfo::GetStackMapForNativePcOffset(uintptr_t pc, InstructionSet isa) const {
uint32_t packed_pc = StackMap::PackNativePc(pc, isa);
// Binary search. All catch stack maps are stored separately at the end.
auto it = std::partition_point(
stack_maps_.begin(),
stack_maps_.end(),
[packed_pc](const StackMap& sm) {
return sm.GetPackedNativePc() < packed_pc && sm.GetKind() != StackMap::Kind::Catch;
});
// Start at the lower bound and iterate over all stack maps with the given native pc.
for (; it != stack_maps_.end() && (*it).GetNativePcOffset(isa) == pc; ++it) {
StackMap::Kind kind = static_cast<StackMap::Kind>((*it).GetKind());
if (kind == StackMap::Kind::Default || kind == StackMap::Kind::OSR) {
return *it;
}
}
return stack_maps_.GetInvalidRow();
}
// Scan backward to determine dex register locations at given stack map.
// All registers for a stack map are combined - inlined registers are just appended,
// therefore 'first_dex_register' allows us to select a sub-range to decode.
void CodeInfo::DecodeDexRegisterMap(uint32_t stack_map_index,
uint32_t first_dex_register,
/*out*/ DexRegisterMap* map) const {
// Count remaining work so we know when we have finished.
uint32_t remaining_registers = map->size();
// Keep scanning backwards and collect the most recent location of each register.
for (int32_t s = stack_map_index; s >= 0 && remaining_registers != 0; s--) {
StackMap stack_map = GetStackMapAt(s);
DCHECK_LE(stack_map_index - s, kMaxDexRegisterMapSearchDistance) << "Unbounded search";
// The mask specifies which registers where modified in this stack map.
// NB: the mask can be shorter than expected if trailing zero bits were removed.
uint32_t mask_index = stack_map.GetDexRegisterMaskIndex();
if (mask_index == StackMap::kNoValue) {
continue; // Nothing changed at this stack map.
}
BitMemoryRegion mask = dex_register_masks_.GetBitMemoryRegion(mask_index);
if (mask.size_in_bits() <= first_dex_register) {
continue; // Nothing changed after the first register we are interested in.
}
// The map stores one catalogue index per each modified register location.
uint32_t map_index = stack_map.GetDexRegisterMapIndex();
DCHECK_NE(map_index, StackMap::kNoValue);
// Skip initial registers which we are not interested in (to get to inlined registers).
map_index += mask.PopCount(0, first_dex_register);
mask = mask.Subregion(first_dex_register, mask.size_in_bits() - first_dex_register);
// Update registers that we see for first time (i.e. most recent value).
DexRegisterLocation* regs = map->data();
const uint32_t end = std::min<uint32_t>(map->size(), mask.size_in_bits());
const size_t kNumBits = BitSizeOf<uint32_t>();
for (uint32_t reg = 0; reg < end; reg += kNumBits) {
// Process the mask in chunks of kNumBits for performance.
uint32_t bits = mask.LoadBits(reg, std::min<uint32_t>(end - reg, kNumBits));
while (bits != 0) {
uint32_t bit = CTZ(bits);
if (regs[reg + bit].GetKind() == DexRegisterLocation::Kind::kInvalid) {
regs[reg + bit] = GetDexRegisterCatalogEntry(dex_register_maps_.Get(map_index));
remaining_registers--;
}
map_index++;
bits ^= 1u << bit; // Clear the bit.
}
}
}
// Set any remaining registers to None (which is the default state at first stack map).
if (remaining_registers != 0) {
DexRegisterLocation* regs = map->data();
for (uint32_t r = 0; r < map->size(); r++) {
if (regs[r].GetKind() == DexRegisterLocation::Kind::kInvalid) {
regs[r] = DexRegisterLocation::None();
}
}
}
}
// Decode the CodeInfo while collecting size statistics.
void CodeInfo::CollectSizeStats(const uint8_t* code_info_data, /*out*/ Stats& stats) {
BitMemoryReader reader(code_info_data);
reader.ReadInterleavedVarints<kNumHeaders>();
stats["Header"].AddBits(reader.NumberOfReadBits());
size_t num_bits;
CodeInfo code_info(code_info_data, &num_bits, [&](size_t i, auto* table, BitMemoryRegion region) {
if (!code_info.IsBitTableDeduped(i)) {
Stats& table_stats = stats[table->GetName()];
table_stats.AddBits(region.size_in_bits());
table_stats["Header"].AddBits(region.size_in_bits() - table->DataBitSize());
const char* const* column_names = table->GetColumnNames();
for (size_t c = 0; c < table->NumColumns(); c++) {
if (table->NumColumnBits(c) > 0) {
Stats& column_stats = table_stats[column_names[c]];
column_stats.AddBits(table->NumRows() * table->NumColumnBits(c), table->NumRows());
}
}
}
});
stats.AddBytes(BitsToBytesRoundUp(num_bits));
}
void DexRegisterMap::Dump(VariableIndentationOutputStream* vios) const {
if (HasAnyLiveDexRegisters()) {
ScopedIndentation indent1(vios);
for (size_t i = 0; i < size(); ++i) {
DexRegisterLocation reg = (*this)[i];
if (reg.IsLive()) {
vios->Stream() << "v" << i << ":" << reg << " ";
}
}
vios->Stream() << "\n";
}
}
void CodeInfo::Dump(VariableIndentationOutputStream* vios,
uint32_t code_offset,
bool verbose,
InstructionSet instruction_set) const {
vios->Stream() << "CodeInfo"
<< " CodeSize:" << code_size_
<< " FrameSize:" << packed_frame_size_ * kStackAlignment
<< " CoreSpillMask:" << std::hex << core_spill_mask_
<< " FpSpillMask:" << std::hex << fp_spill_mask_
<< " NumberOfDexRegisters:" << std::dec << number_of_dex_registers_
<< "\n";
ScopedIndentation indent1(vios);
ForEachBitTableField([this, &vios, verbose](size_t, auto member_pointer) {
const auto& table = this->*member_pointer;
if (table.NumRows() != 0) {
vios->Stream() << table.GetName() << " BitSize=" << table.DataBitSize();
vios->Stream() << " Rows=" << table.NumRows() << " Bits={";
const char* const* column_names = table.GetColumnNames();
for (size_t c = 0; c < table.NumColumns(); c++) {
vios->Stream() << (c != 0 ? " " : "");
vios->Stream() << column_names[c] << "=" << table.NumColumnBits(c);
}
vios->Stream() << "}\n";
if (verbose) {
ScopedIndentation indent1(vios);
for (size_t r = 0; r < table.NumRows(); r++) {
vios->Stream() << "[" << std::right << std::setw(3) << r << "]={";
for (size_t c = 0; c < table.NumColumns(); c++) {
vios->Stream() << (c != 0 ? " " : "");
if (&table == static_cast<const void*>(&stack_masks_) ||
&table == static_cast<const void*>(&dex_register_masks_)) {
BitMemoryRegion bits = table.GetBitMemoryRegion(r, c);
for (size_t b = 0, e = bits.size_in_bits(); b < e; b++) {
vios->Stream() << bits.LoadBit(e - b - 1);
}
} else {
vios->Stream() << std::right << std::setw(8) << static_cast<int32_t>(table.Get(r, c));
}
}
vios->Stream() << "}\n";
}
}
}
});
// Display stack maps along with (live) Dex register maps.
if (verbose) {
for (StackMap stack_map : stack_maps_) {
stack_map.Dump(vios, *this, code_offset, instruction_set);
}
}
}
void StackMap::Dump(VariableIndentationOutputStream* vios,
const CodeInfo& code_info,
uint32_t code_offset,
InstructionSet instruction_set) const {
const uint32_t pc_offset = GetNativePcOffset(instruction_set);
vios->Stream()
<< "StackMap[" << Row() << "]"
<< std::hex
<< " (native_pc=0x" << code_offset + pc_offset
<< ", dex_pc=0x" << GetDexPc()
<< ", register_mask=0x" << code_info.GetRegisterMaskOf(*this)
<< std::dec
<< ", stack_mask=0b";
BitMemoryRegion stack_mask = code_info.GetStackMaskOf(*this);
for (size_t i = 0, e = stack_mask.size_in_bits(); i < e; ++i) {
vios->Stream() << stack_mask.LoadBit(e - i - 1);
}
switch (static_cast<Kind>(GetKind())) {
case Kind::Default: break;
case Kind::Catch: vios->Stream() << ", Catch"; break;
case Kind::OSR: vios->Stream() << ", OSR"; break;
case Kind::Debug: vios->Stream() << ", Debug"; break;
}
vios->Stream() << ")\n";
code_info.GetDexRegisterMapOf(*this).Dump(vios);
for (InlineInfo inline_info : code_info.GetInlineInfosOf(*this)) {
inline_info.Dump(vios, code_info, *this);
}
}
void InlineInfo::Dump(VariableIndentationOutputStream* vios,
const CodeInfo& code_info,
const StackMap& stack_map) const {
uint32_t depth = Row() - stack_map.GetInlineInfoIndex();
vios->Stream()
<< "InlineInfo[" << Row() << "]"
<< " (depth=" << depth
<< std::hex
<< ", dex_pc=0x" << GetDexPc();
if (EncodesArtMethod()) {
ScopedObjectAccess soa(Thread::Current());
vios->Stream() << ", method=" << GetArtMethod()->PrettyMethod();
} else {
vios->Stream()
<< std::dec
<< ", method_index=" << code_info.GetMethodIndexOf(*this);
}
vios->Stream() << ")\n";
code_info.GetInlineDexRegisterMapOf(stack_map, *this).Dump(vios);
}
} // namespace art